Modern people suffer from skin itching, wrinkling, allergy, and other dry skin related problems. The skin has an adequate moisture content, which lays the basis for skin barrier, absorption, metabolism, and other physiological functions. Adequate hydration is favorable to enzymatic reaction, and can facilitate the maturization of the stratum corneum and allow the stratum corneum to remain elastic. Adequate hydration is also favorable to the expansion, and reduction in structural compactness, of the cells in the stratum corneum, such that the permeability is increased. Regular reflection from a stratum corneum layer with a high moisture content gives rise to a bright glow. In contrast, the light is non specularly reflected from a dry and squamous stratum corneum layer, such that the skin looks dim. Therefore for a majority of women, the skin protection is currently focused on moisturizing of the skin, and thus the moisturizing efficacy has become a critical aspect of the skin care products.
The moisture retention ability of the skin mainly depends on the stratum corneum, since the stratum corneum functions as a barrier against water loss. The stratum corneum comprises water soluble moisturizing substances such as amino acids or salts thereof, carbohydrates, and so on (referred to as natural moisturizing factors, NMFs), and oil ingredients such as cellular lipids and sebum (those present in epidermis are referred to as epidermal sebum), in which the natural moisturizing factors account for 30% and the oil ingredients account for 11%. The oil ingredients are in association with, or encircle the natural moisturizing factors, to prevent them from outflow, thus playing a role in controlling the moisture volatilization. In addition, several aquaporins exist in the skin, which affect the transport of water in the skin. Aquaporin 3 (AQP3) is the mostly expressed aquaporin in the skin, which is rather abundant in human epidermal keratinocytes and stratum corneum as detected by RT-PCR. AQP3 is of great importance for water retention in keratinocytes. It is found through observations on the phenotype of AQP3 gene knockout nude mice that the mice are substantially normally developed, except that the moisture content in the epidermal keratinocytes in the AQP3 gene knockout nude mice is considerably reduced, and the water loss is obviously higher than that in normal mice, when exposed to dry conditions.
“Healthy and natural” is the development philosophy of the cosmetic industry. China is long in history of manufacturing and using natural plant cosmetics and rich in practical experiences, and has a technical superiority. Moreover, China has vast territory and rich natural resources, where various distinctive plants are grown due to its unique geographical environment and climatic conditions. Because of their different characteristics, these plants have long been used in cosmetology, and have the effect of nourishing the skin and protecting the skin against the adverse effects from external harmful agents.
In view of this, a cosmetic additive is developed from natural plants in this patent, which is mainly characterized by moisturizing efficacy and also by anti-aging and anti-allergic efficacies. The extracts from many plants are combined, which synergize by means of film forming, water retention, maintenance of normal physiological functions of aquaporins, and others to exert comprehensive moisturizing, anti-wrinkle, and anti-allergic effects.